What is Android rooting ?

Rooting is the process of allowing users of smartphones, tablets and other devices running the Android operating system to attain privileged control over various Android’s subsystems.

Root is just a user with elevated permissions, who can do anything to any file or folder in the system. It will allow the user to access the entire operating system. The user is able to customize anything on Android device. User can run more apps, overclock or underclock the processor, replace the firmware etc.